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In 1931 the International Commission on Illumination (CIE) published the CIE 1931 color spaces which define the relationship between the visible spectrum and human color vision. [1] [2] The CIE color spaces are mathematical models that comprise a "standard observer", which is a static idealization of the color vision of a normal human. A useful ...
Researchers use daylight as the benchmark to which to compare color rendering of electric lights. In 1948, daylight was described as the ideal source of illumination for good color rendering because "it (daylight) displays (1) a great variety of colors, (2) makes it easy to distinguish slight shades of color, and (3) the colors of objects around us obviously look natural".
The same discrepancy applies to all illuminants in the D series—D 50, D 55, D 65, D 75 —and can be "rectified" by multiplying the nominal color temperature by ; for example … = for D 65. To determine the D-series SPD (S D ) that corresponds to those coordinates, the coefficients M 1 and M 2 of the characteristic vectors S 1 and S 2 are ...
The color rendering index (CRI) of 1974 is the product of a CIE committee's study on the topic of color rendering. It uses the American colorimetric approach with a panel of human subjects instead of requiring spectrophotometry. Eight samples of varying hue would be alternately lit with two illuminants, and the color appearance compared.
Color temperature is a parameter describing the color of a visible light source by comparing it to the color of light emitted by an idealized opaque, non-reflective body. The temperature of the ideal emitter that matches the color most closely is defined as the color temperature of the original visible light source.
Color quality scale (CQS) is a color rendering score – a quantitative measure of the ability of a light source to reproduce colors of illuminated objects. Developed by researchers at NIST [ 1 ] the metric aims to overcome some of the issues inherent in the widely used color rendering index (CIE Ra, 1974).
The CIELAB color space, also referred to as L*a*b*, is a color space defined by the International Commission on Illumination (abbreviated CIE) in 1976. [a] It expresses color as three values: L* for perceptual lightness and a* and b* for the four unique colors of human vision: red, green, blue and yellow.
Hunter Lab (also known as Hunter L,a,b) is a color space defined in 1948 [1] [2] by Richard S. Hunter.It was designed to be computed via simple formulas from the CIEXYZ space, but to be more perceptually uniform.